RU2131525C1 - Modular engine power control - Google Patents

Abstract

FIELD: power-plant engineering. SUBSTANCE: on-line control of engine power is effected by varying time intervals between working cycles for which purpose pistons are delayed in initial position for completing working cycle for time period inversely proportional to power requirement. Control system functions to organize processes of fuel combustion and expansion of combustion products within engine cylinder. EFFECT: improved economic efficiency of free-piston engines when carrying partial loads. 2 dwg

Description

 The invention is within the scope of piston internal combustion engines.

 The proposed method for controlling the power of an internal combustion engine involves the use of the principle of operation of free-piston gas generators, the description of which is given in the monograph of Candidate of Technical Sciences P.A. Shelest "Shaft-less gas generators" Mashgiz, State Scientific and Technical Publishing House of Mechanical Engineering, M., 1960.

 The principle of operation of the free-piston gas generator. Before starting the pistons of the machine 1 / cm. figure 1 / and the pistons of the compressor 2 connected to them are bent to extreme positions. Compressed air is supplied from the starting reservoir to the buffer cavities 3, which pushes the pistons of the compressor and the machine in the opposite direction. The pistons approach and compress the air in the combustion chamber 4. Air from the compressor cavities 5 through the bypass valves 6 flows into the air receiver 7. At a moment close to the maximum piston approximation, fuel is supplied to the combustion chamber by the nozzle 8. The fuel ignites and the combustion products, expanding, change the direction of movement of the pistons. Atmospheric air through the inlet valves 9 enters the cavity of the compressor, and the air in the buffer cavities is compressed. Before the pistons reach their extreme positions, the outlet 10 and then the inlet 11 windows open sequentially. The combustion products and part of the purge air from the air receiver through the inlet and outlet windows enter the pressure receiver 12 and then to the turbine 13. The torque is removed from the turbine shaft 14. At the extreme positions, the pistons change direction under the influence of air in the buffer cavities movement and duty cycle repeated. The power control of free-piston gas generators is carried out by changing the frequency of duty cycles by varying the dose of fuel supplied to the combustion chamber for each duty cycle.

 SUMMARY OF THE INVENTION The main feature of the principle of operation of free-piston gas generators is that there is no rigid kinematic connection between the pistons of the machine and the power take-off shaft. It is by virtue of this feature that it is possible to implement power control not by fuel metering, but by the corresponding load by changing the time intervals between duty cycles with constant masses of fuel and air supplied to each duty cycle.

 Structurally, such an engine can be designed as a single module, which includes all the devices necessary to ensure its operability, or as a complex of several modules of the same type, united by a common control system. Therefore, the engine with the proposed method of power control is conventionally called a modular engine.

 A necessary condition for the implementation of the proposed method of controlling engine power is the absence of a rigid feedback between the nature of the load and the law of motion of the pistons. Therefore, the kinetic energy of the pistons must be transmitted to the power take-off shaft in ways that exclude this feedback — pneumatic, hydraulic, electric, and other methods.

 The principle of operation of a modular engine. When illustrating the principle of operation of a modular engine, it is assumed that the kinetic energy of the pistons is transmitted to the power take-off shaft electrically.

 The module consists of a machine that converts the chemical energy of the fuel into the kinetic energy of the pistons, a control system for the duration of the piston delays and the parameters of the operating cycles, and an electric motor for the power take-off shaft.

 A control system for piston delay times and 1 / cm duty cycle parameters. figure 2 / provides the automation of the module and includes an accelerator 2, processor 3, switch 4, battery 5, a set of sensors for the parameters of the duty cycle 6 and the clamps of the pistons in the initial states 7.

 The electric motor of the power take-off shaft 8 converts the electric power generated in the solenoids 9 into the torque of the power take-off shaft.

 If before starting the pistons of the machine 10 and the pistons of the compressor 11 connected to them are not in their original positions, the processor sends a signal to the switch, which connects the battery to the solenoids. An impulse of electric power of the corresponding polarity is supplied to the solenoids and the magnetic fields of the solenoids arising from this move the pistons to their original positions. To ensure that the machine is ready for the start of the working cycle, the pistons are held by the piston retainers, and the piston position sensors signal the initial position of the pistons to the processor.

 When the engine is started, the signal from the accelerator goes to the processor, which connects the battery to the solenoid windings through the switch and sends a signal to the piston clamps. The clamps release the pistons, and the current flowing through the windings of the solenoids creates magnetic fields of a certain strength and direction, as a result of which the pistons of the machine and compressor begin to counter-move. The magnitude of the current in the solenoid windings is determined by the processor based on the mass and physico-chemical properties of the fuel and air entering the combustion chamber in such a way that the law of piston movement provides the pressure necessary for complete combustion of the fuel with a minimum duty cycle time. Air from the cavities of the compressor 12 through the bypass valves 13 enters the receiver 14. Near the point of maximum convergence of the pistons, the processor nozzle 15 delivers fuel to the combustion chamber 16. The fuel ignites and the combustion products, expanding, change the direction of movement of the pistons. Atmospheric air through the inlet valves 17 enters the cavity of the compressor. Gradually open the outlet 18 and inlet 19 windows. Exhaust gases through the exhaust manifold 20 flow out, and air from the receiver through the inlet and outlet windows blows the cylinder. At the same time, when the pistons move from the center to the periphery, electromotive force is generated in the solenoid windings and, through the commutator, enters the power take-off shaft motor and the battery. The battery is charged to the level necessary to provide the energy for initiating the next working cycle. When the module operates in maximum power mode, the duty cycle is repeated immediately without interruption. In the case of partial loads on the module, the processor sets the time interval of the piston delay between working cycles inversely proportional to the amount of decrease in the generated power, and when the load increases, the time interval decreases to zero.

 From the description of the principle of operation of a modular engine it can be seen that the power control process is divided into two independent processes - the process of maneuvering the current engine power by changing the length of time intervals between duty cycles and the process of dispensing masses of fuel and air supplied to the engine, independent of the load into the combustion chamber for each working cycle, in combination with the degree of compression of the working fluid in accordance with the physicochemical characteristics of the fuel used. The absence of a rigid feedback between the nature of the load on the engine and the law of motion of the pistons allows a wide range of control of the parameters of the operating cycles, providing the engine, along with high environmental economic indicators, the properties of a multi-fuel engine. Depending on the specific operating conditions of the vehicle, the requirements of high environmental friendliness or increased engine power may come to the fore. To satisfy them, the control system for the duration of piston delays and the parameters of the operating cycles provides for a switch of the engine operating modes from ecological to forced mode.

 Maneuvering the length of time intervals between duty cycles provides the engine with extremely high throttle response. The minimum time for the engine to reach full power from zero to maximum is limited only by the time of a single duty cycle and the inertia of the power take-off motor. In addition, the very concept of idling loses its meaning, since the engine starts, in fact, every time at the beginning of each working cycle. The engine only works when propulsion is required. When the vehicle moves on a slope, by inertia and at stops, even the shortest, the engine does not turn on.

It was mentioned above that, by analogy with a multi-cylinder engine, a modular engine can be designed as a complex of the same type of modules under the control of a common control system. In the multi-module version, engine power control can be carried out by changing the time intervals between the operating cycles of one or more modules in series or in parallel. The main features of multimodular engines should primarily include:
- survivability - the failure of one or even several modules while the vehicle is moving will only partially reduce the dynamic characteristics of the engine, but will not deprive it of working capacity and the driver need not leave the cab and even interrupt the movement;
- increased maintainability - restoration of the engine’s working capacity in full can be carried out by replacing a faulty module with a working one or outdated with a modernized one;
- plasticity of the architecture - the ability to place engine elements and even entire modules in various places of the vehicle.

 The listed qualities of multimodular engines can be useful for using them both on public transport and when equipping military vehicles and vehicles designed to operate in harsh conditions, far from the means of repair and maintenance. A new type of pre-sale preparation will appear in car dealerships - equipment of a vehicle with modules of various modifications at the request of the buyer. It is also possible a phased build-up of modular multiplicity or partial equipment of the engine with modules.

 In FIG. 1 is a schematic diagram of a gas generator with free-moving pistons.

 Figure 2 is a schematic diagram of a modular engine.

Claims (1)

 A method of controlling the power of a free-piston internal combustion engine, characterized in that the operational control of the engine power is carried out by changing the duration of the time intervals between duty cycles or between series of continuously following successive work cycles by delaying the engine pistons in the initial positions for completing the next duty cycle, inversely proportional the amount of current power generated by the engine, for which a system is provided in the engine structure control the duration of time intervals between duty cycles or between series of continuously successive work cycles, through which the operator controls the current engine power, and the organization of the processes of fuel combustion and expansion of combustion products in the engine cylinder with the aim of optimizing them is controlled by a control system for controlling the working parameters cycles independently of the nature of the load on the engine, for which the kinematic energy of the pistons is transmitted to the power take-off shaft of Tell means that eliminates the dependence of the parameters of cycles on the nature of the load on the engine.

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